A silicon photodiode is converted to a low energy charged particle radiation detector. The window thickness of the fabricated detector is evaluated to be 50μg/cm2. The area of the depletion region is 13.2 mm2and the depth of it is estimated to be about 100 pm. The energy resolution (FWHM) is 14.5 keV for α-particles from241Am and 2.5 keV for conversion electrons from109Cd, respectively.
Effects of the pressure variation of counting gas on the efficiency function were examined using a 4πβ-γ coincidence counting system with a pressurized proportional counter. The results showed that the pressure variation of about ten kPa could not give large effects on the efficiency function and that a non-flow type of pressurized proportional counter with a simple gas control system could work well in the case of the pressure higher than 1 MPa, an ordinary pressure for the counting.